1. Field of the Invention
This invention is in the field of devices for finishing surfaces; more specifically, this invention is in the field of abrading means for belt sanders and the like.
2. Description of the Prior Art
In my U.S. Pat. No. 4,028,781, I disclose and claim a metal sheet having perforations therein, the sheet being useful in place of sandpaper for reciprocal and orbital sanding machines. While such a sheet has utility and a much greater durability and life than conventional sandpaper or emery cloth, it is by its very nature restricted to the general line of machines which provide a reciprocating motion, and obviously cannot be used on a belt sander.
There have been other attempts to provide abrasive means useful with a rotary application. Bertrand, in U.S. Pat. No. 1,789,298, shows an abrading strip helically wound on a drum, the ends of the strip being secured to the drum at the ends thereof in such a fashion that the surface of the drum is effectively covered with the strip. By this arrangement, the drum can be used as an abrading device operating in the rotational mode as opposed to the reciprocal. Bertrand, however, has no provision for the application of any part of the abrading surface in the planar conformation, the strip conforming to the curved drum surface.
Caston, in U.S. Pat. No. 2,518,448, makes provision for both a rotary application and the possibility of applying a planar portion of the device to the work. Caston discloses an endless belt made of flexible steel, being carried between two drums, whereby either a planar or a curvilinear surface may be presented to the work. There is no disclosure in the '448 patent, however, of the nature of the joinder of the ends of the original metal band to form the endless belt.
In using endless metal belts, one problem which has been observed is that the weld area causes the belt surface to rise in relation to the drum as that area of the belt passes over the drum. In the planar portion of the belt, the problem is not so acute, but a different problem arises when the weld line is perpendicular to the direction of travel of the belt, that problem being that there is a gap in the abrading surface.